福建省农村有机废弃物及沼气潜力评估

根据2003年福建省统计年鉴统计数据,计算了福建省农村有机废弃物以及其沼气潜力。目前,我省每年可有各种畜禽粪便100.31×106t(TS=20%),可产沼气96.8亿m3;农作物秸秆10.35×106t,60%可以用来产沼气,可产沼气12亿m3。按我省120万户农户计算,户均可拥有沼气量为9080m3,可完全解决农村生活用能。     

Technical–economical analysis of the Saveh biogas power plant

The resource limitation of fossil fuels and the problems arising from their combustion has led to widespread research on the accessibility of new and renewable energy resources. Solar, wind, thermal and hydro sources, and finally biogas are among these renewable energy resources. But what makes biogas distinct from other renewable energies is its importance in controlling and collecting organic waste material and at the same time producing fertilizer and water for use in agricultural irrigation. Unlike other forms of renewable energy, biogas neither has any geographical limitations and required technology for producing energy and nor is it complex or monopolistic. Considering the ever increasing amount of different types of organic waste materials (about 15 million tonnes) in Iran, working on the control of waste material and biogas production becomes inevitable.In this paper, biogas and the benefits from its production are discussed, as is the technical-economic analysis of the Saveh biogas power plant as a case study.     

Biomass and biogas energy in Thailand: Potential, opportunity and barriers

Biomass has been traditional energy source in rural Thailand for decades. Country modernization, instead of reducing the biomass energy consumption, has continuously increased its utilization for both households and production of modern energy. While the GDP/capita was triple during 1980–1996, the biomass energy consumption increased by 68%, and expected to be higher as signaled by the increasing number of new biomass power plants. The legal and financial support frameworks to increase renewable energy utilization was launched in 1992 aiming for the country to depend less on imported energy, which at present accounted for 7% of GDP. In this paper, biomass and biogas energy situation in Thailand is presented. Resource potential, the promotion program and its success and failure were analyzed to suggest new policy option recommendation. The amount of agricultural residues is about 61 million ton a year, of which 41 million ton, which is equivalent to about 426 PJ of energy, was unused. The most promising residues are rice husk, bagasse, oil palm residue and rubber wood residue, merely due to their availability at the mills, which heat–power cogeneration is feasible. Biogas resources are from industrial wastewater and live stocks manure, which have potential of 7800 and 13,000 TJ/y, respectively. Instead of having the legal and financial support frameworks, the success of biomass energy program in Thailand is doubtful. Discussion on mechanisms and measures based on the past policy, which has been implemented for over a decade, is presented. From lessons learned we propose new policy approach to, in our opinion, overcome the biomass energy utilization barrier in Thailand.     

福建省规模化养猪场粪便沼气潜力评估及分布特征

以畜牧部门统计数据为依据,对福建省规模化养猪场粪便资源产沼气潜力进行了评估并介绍了分布特征,结果表明2007年福建省规模化养殖场存栏生猪613.68万头,粪便资源干物质含量为101.16万t,沼气潜力为4.25亿m3,主要分布在福州市、龙岩市、南平市以及漳州市。     

多元原料混合发酵制备沼气技术研究进展

目前,我国沼气的发酵原料主要是禽畜粪便和农作物秸秆,随着厌氧发酵技术的发展,更多种类废弃物也逐步受到人们的关注。有机废弃物沼气化利用在我国生态文明建设中有着重大意义。论文综述了我国生物质资源,如禽畜粪便、农作物秸秆、农产品加工废弃物、市政有机废弃物和能源作物的特性和作为沼气发酵原料的优缺点,比较了这些原料的沼气生产潜力,探讨了混合原料发酵技术及重要的几种沼气发酵外源添加剂。     

A pioneering study of biomethane and hydrogen production from the wine industry in Brazil: Pollutant emissions,electricity generation and urban bus fleet supply

The thematic area studied in this paper considers environmental issues such as atmospheric pollution from the combustion of fossil fuels, and the environmental impacts from the generation of urban agricultural solid wastes. This study has estimated the potential for hydrogen and biogas production from solid urban waste (SUW) and wine waste from Bento Gonçalves, which is a region in Brazil with the largest wine throughput and subsequent waste generation, thus providing a potential high-energy feedstock. The resulting hydrogen and biogas are assumed to displace the existing fuels in the local bus fleet. The analytical work consisted of three scenarios - scenario 1: production of biogas using SUW, sourced exclusively from the municipality of Bento Gonçalves; Scenario 2: the possibility to supply SUW from Bento Gonçalves and surrounding cities, to produce biogas; Scenario 3: the possibility to use wine waste and SUW for biogas production. Scenario 3 showed the greatest energy yield with 37.9 Gg of biomethane produced per year, which can supply the entire public bus fleet of Bento Gonçalves. The resulting hydrogen production potential using steam reforming of biomethane is 1.09 E+08 Nm³H₂.d^?1 which can generate 2.62 TW h.year^?1 of electrical energy, avoiding approximate emissions of 355 ktonCO₂.year^?1. These findings indicate value in the production of biogas from urban and agricultural wastes, especially for the generation of methane, hydrogen and useful energy outputs. Its production from renewable and clean sources contributes to the gradual transformation of an economy currently dependent on non-renewable resources into a circular and renewable economy.     

Status and potential of biogas energy from animal wastes in Turkey

Biogas is a potentially important energy source that can be used for the production of heat, electricity and fuel. It can be produced at wastewater treatment plants, landfills, food and other industrial operations throughout the world. There is largely untapped potential in agricultural operations where animal waste is often land applied or otherwise disposal of without conversion to energy. According to the last agricultural census (2009) in Turkey; there are a total of 3,076,650 agricultural enterprises and approximately 70% of these enterprises are running livestock farming. 10,811,165 of total animal is cattle, 26,877,793 of total animal is small ruminant and 234,082,206 is poultry. The amount of wet waste of these animals is about 120,887,280 t. These wastes could be a major problem for enterprises and cannot be utilized properly. The best way to utilize waste is to produce biogas. In this study, biogas amount which will be obtained from animal waste was calculated for all provinces by using the number of livestock animals and also considering various criteria such as the rate of dry matter and availability. Animal origin waste map of Turkey was also produced with these calculated values. The biogas energy potential of Turkey was found to be 2,177,553,000 m³ (2.18 Gm³) by using the animal numbers in the last agricultural census (2009). The total biogas potential is originated from 68% cattle, 5% small ruminant and 27% poultry. Biogas energy equivalence of Turkey is approximately 49 PJ (1170.4 ktoe). When the prepared waste map is examined; provinces that have more than 1 GJ of biogas energy potential are found to be; Bolu, Bal?kesir, ?zmir, Sakarya, Konya, Manisa, Erzurum, Afyon, Kars and Ankara respectively.     

Estimate of the electric energy generating potential for different sources of biogas in Brazil

The increasing interest in the recuperation of the biogas coming from organic residues, associated with its energetic use is a subject that has been widely discussed. Biogas was merely seen as a sub-product obtained from anaerobic decomposition (without oxygen) of organic residue. In the paper is carried out an evaluation of the quantities of organic residues coming out from the sugar and alcohol industry (vinasse), urban solid and liquid wastes (garbage and sewage) and livestock residues (bovine and swine manure) in Brazil. Finally the electricity generation potential of biogas out of the evaluated sources of organic residues in Brazil is estimated. The results of this study indicate that the potential regarding the production of biogas out of the aforementioned organic residues of electricity production using could meet an energy demand of about 1.05 to 1.13 %. Constraints for biogas energy utilization are identified and discussed.     

Standalone hybrid system energy management optimization for remote village considering methane production from livestock manure

Recently, many efforts have been done to overcome increasing fuel consumption. One of the vital solutions is utilization of standalone renewable energy resources hybrid systems. This paper attempts to develop a cost-effective methodology to ascertain optimal design and energy management for a remote village. Different energy resources such as wind and solar, fuel cell, and energy storage systems are employed to satisfy total demands including agriculture, residential, school, and health center. Different hydrogen production methods are proposed to verify the efficiency of the developed methodology. In the proposed village, different waste types such as rice husk, maize straw, livestock, and residential wastes are used to generate the required hydrogen for fuel cells to generate electricity. The main objective of the proposed methodology is minimizing the total cost of the village including total costs of each Distributed Generation (DG), cost of natural gas consumption, penalty for interruption the demands, and cost of CO₂ emission. A Particle Swarm Optimization (PSO) algorithm is employed to solve the optimization problem by minimizing the total system costs while the customers required Loss of Power Supply Probability (LPSP) is satisfied. The suggested hybrid system not only increases the renewable energy penetration but also decreases the natural gas consumption. The results achieved in the course of the present study depict that utilization of energy produced from different types of wastes plays a significant role in conserving fossil fuels and overcoming the fossil fuels depletion. It is concluded from the results that there is about a 17.46% reduction in natural gas consumption when all available waste is utilized. In addition, considering 100% availability for the animal manure reduces the natural gas consumption by reformer from 2.373 to 1.605 million liters which means reduction of the natural gas consumption is 32.35%. The results conclude that H₂ produced by livestock waste is dominating among available wastes. However, there is about 18% reduction in the Cost of Energy (COE), when 100% availability is considered for this type of waste.     

Methane generation in landfills

Methane gas is a by-product of landfilling municipal solid wastes (MSW). Most of the global MSW is dumped in non-regulated landfills and the generated methane is emitted to the atmosphere. Some of the modern regulated landfills attempt to capture and utilize landfill biogas, a renewable energy source, to generate electricity or heat. As of 2001, there were about one thousand landfills collecting landfill biogas worldwide. The landfills that capture biogas in the US collect about 2.6 million tonnes of methane annually, 70% of which is used to generate heat and/or electricity. The landfill gas situation in the US was used to estimate the potential for additional collection and utilization of landfill gas in the US and worldwide. Theoretical and experimental studies indicate that complete anaerobic biodegradation of MSW generates about 200 Nm³ of methane per dry tonne of contained biomass. However, the reported rate of generation of methane in industrial anaerobic digestion reactors ranges from 40 to 80 Nm³ per tonne of organic wastes. Several US landfills report capturing as much as 100 Nm³ of methane per ton of MSW landfilled in a given year. These findings led to a conservative estimate of methane generation of about 50 Nm³ of methane per ton of MSW landfilled. Therefore, for the estimated global landfilling of 1.5 billion tones annually, the corresponding rate of methane generation at landfills is 75 billion Nm³. Less than 10% of this potential is captured and utilized at this time.     

Bio-fuels from Agricutural Residues

Abstract

Bio-fuels, such as bio-oil, bio-char, and bio-gas, can be obtained from agricultural residues. Agricultural residues are potential renewable energy resources such as biogas from anaerobic digestion, bio-oil from pyrolysis, and bio-char from carbonization and slow pyrolysis processes. Pyrolysis process of agricultural residues are the most common and convenient methods for conversion into bio-oil and bio-char. When the pyrolysis temperature increased, the bio-char yield decreased. The bio-char yield increased with increasing particle size of the sample. The yield of bio-oil from pyrolysis of the samples increased with temperature. Anaerobic biogas production is an effective process for conversion of a broad variety of agricultural biomass to methane to substitute natural gas and medium calorific value gases.     

Insights into the production potential and trends of China's rural biogas

China, one of the countries in the world abundant in agricultural wastes, has a great potential for rural biogas production. As a strategy for building a new socialist countryside and sustainable agriculture in rural China, the development of biogas is an important means to convert agricultural wastes to clean and safe energy, thereby reducing the need for fossil fuel and alleviating environmental pollution. This study presents an assessment of the biogas production potential, its current development state, and perspectives of agricultural wastes in rural China. Estimated data show that annual biogas potential from agricultural wastes is approximately (3350.58 ± 669.28) × 10⁸ m³ (equal to 239.22 ± 47.78 million tons of equivalent standard coal); such potential has been underutilized in the past. By analyzing and summarizing the direction for future development and various benefits of rural biogas in China, we present burning questions and countermeasures for biogas development and recommend that the future development of rural biogas in China should focus on both household‐scale and large‐scale development, giving priority to the establishment of large‐scale biogas engineering and biogas plants, improvement of biogas comprehensive utilization level, and construction of a reticular model of systemized green agricultural engineering linked with biogas to solve completely the problem of agricultural waste accumulation and improve the living conditions in rural China. Copyright © 2015 John Wiley & Sons, Ltd.     

Biogas Production and Utilization Potential of Wastewater Treatment Sludge

Abstract

Municipal wastewater treatment plants generate sludge as a by-product of the physical, chemical and biological processes used in the treatment of wastewater. Generally, this sludge must be subject to some form of treatment in order to alter its character. By using anaerobic digestion in the treatment of wastewater sludge, methane gas is produced and it is known as biogas. It must not only be seen as a renewable energy source, but even more as one of the promising solutions to the large environmental problem concerning waste handling, water pollution, CO₂ emission, etc. This article presents the biogas generation from wastewater treatment sludge, its energy potential and also its usage in some treatment plants operated in Turkey. Although the estimation of recoverable energy from municipal wastes and sewage is difficult to assess, total recoverable bioenergy potential is estimated as being 16,920 ktoe. Of this, 1,300 ktoe of municipal wastes and sewage whereas biogas production potential is 1.5–2 Mtoe in Turkey.     

Biogas production from municipal sewage sludge (MSS)

Biogas is produced by anaerobic (oxygen free) digestion of organic materials such as sewage sludge, animal waste, and municipal solid wastes (MSW). As sustainable clean energy carrier biogas is an important source of energy in heat and electricity generation, it is one of the most promising renewable energy sources in the world. Biogas is produced from the anaerobic digestion (AD) of organic matter, such as manure, MSW, sewage sludge, biodegradable wastes, and agricultural slurry, under anaerobic conditions with the help of microorganism. Biogas is composed of methane (55–75%), carbon dioxide (25–45%), nitrogen (0–5%), hydrogen (0–1%), hydrogen sulfide (0–1%), and oxygen (0–2%). The sewage sludge contains mainly proteins, sugars, detergents, phenols, and lipids. Sewage sludge also includes toxic and hazardous organic and inorganic pollutants sources. The digestion of municipal sewage sludge (MSS) occurs in three basic steps: acidogen, methanogens, and methanogens. During a 30-day digestion period, 80–85% of the biogas is produced in the first 15–18 days. Higher yields were observed within the temperature range of 30–60°C and pH range of 5.5–8.5. The MSS contains low nitrogen and has carbon-to-nitrogen (C/N) ratios of around 40–70. The optimal C/N ratio for the AD should be between 25 and 35. C/N ratio of sludge in small-scale sewage plants is often low, so nitrogen can be added in an inorganic form (ammonia or in organic form) such as livestock manure, urea, or food wastes. Potential production capacity of a biogas plant with a digestion chamber size of 500 m³ was estimated as 20–36 × 10³ Nm³ biogas production per year.     

A biofuel strategy for Ireland with an emphasis on production of biomethane and minimization of land-take

Increasing energy consumption has exerted great pressure on natural resources; this has led to a move towards sustainable energy resources to improve security of supply and to reduce greenhouse gas emissions. However, the rush to the cure may have been made in haste. Biofuels in particular, have a bad press both in terms of competition with good agricultural land for food, and also in terms of the associated energy balance with the whole life cycle analysis of the biofuel system. The emphasis is now very much on sustainable biofuel production; biofuels from wastes and lignocellulosic material are now seen as good sustainable biofuels that affect significantly better greenhouse gas balances as compared with first generation biofuels. Ireland has a significant resource of organic waste that could be a potential source of energy through anaerobic digestion. Ireland has 8% of the cattle population of the EU with less than 1% of the human population; as a result 91% of agricultural land in Ireland is under grass. Residues such as slurries and slaughter waste together with energy crops such as grass have an excellent potential to produce biogas that may be upgraded to biomethane. This biomethane may be used as a natural gas substitute; bio-compressed natural gas may then be an avenue for a biofuel strategy. It is estimated that a maximum potential of 33% of natural gas may be substituted by 2020 with a practical obtainable level of 7.5% estimated. Together with biodiesel from residues the practical obtainable level of this strategy may effect greater than a 5% substitution by energy of transport. The residues considered in this strategy to produce biofuel (excluding grass) have the potential to save 93,000 ha of agricultural land (23% of Irish arable land) when compared to a rapeseed biodiesel strategy.     

Investigation of agricultural and animal wastes in Greece and their allocation to potential application for energy production

Agricultural and animal wastes constitute a high proportion of biomass in Greece, and are able to play an important role towards the satisfaction of heat and/or energy and related material supply, with respect to the environmental protection targets. This paper describes pyrolysis, gasification and combustion, as a potential agricultural and animal waste exploitation method, and presents a comparison between those treatments when utilized as a source for renewable energy. The aim of the present work was to strengthen the interest in agricultural and animal waste potential for energy production in Greece, through a methodology for the feasibility of utilization of those kinds of wastes as renewable energy resources.A combination of technical, economic and environmental issues is presented here, and focus on the benefits that thermochemical conversion is able to offer, either in investigation or in future technological application for alternative exploitation methods of animal and agricultural wastes.     

Land application of organic waste – Effects on the soil ecosystem

Growing populations and the increasing use of existing resources has led to growth in organic waste emissions. Therefore, a sustainable approach to managing this waste has become a major concern in densely populated areas. Biological treatment is an efficient method for reducing the amount of organic waste, and for producing energy. A large number of biogas plants and compost facilities that use organic waste as a substrate for electricity and fuel production are being built around the world. The biological treatment process in these plants produces large amounts of organic waste, and there is therefore a growing need to find a sustainable use for this material. Organic waste, such as biogas residues and compost can be a valuable fertilizer for agricultural soils. They can serve as a source of plant nutrients and can also improve soil structure and water holding capacity. However, as organic residues are known to contain both heavy metals and organic contaminants there is a need for long term field experiments to ensure that soil and plant quality is maintained. In order to investigate the potential risks and benefits of using organic waste in agriculture, an 8 year field experiment was established in central Sweden. Under realistic conditions, compost and biogas residues from source-separated household waste were compared with traditional mineral fertilizer. We examined crop yield and soil chemical and microbiological properties. The main conclusion from the field experiment was that biogas residues resulted in crop yields almost as high as the mineral fertilizer NPS. In addition, several important soil microbiological properties, such as substrate induced respiration, potential ammonium oxidation and nitrogen mineralization were improved after application of both biogas residues and compost. Moreover, no negative effects could be detected from using either of the organic wastes. In particular the genetic structure of the soil bacterial community appeared to resist changes caused by addition of organic waste.     

Energy situation in Mozambique: A review

The need to increase energy security and promote development, especially in rural areas has forced many developing countries in southern Africa, like Mozambique to take several actions toward development of several infrastructures and legislations for production and use of liquid biofuels. The main objective of this study is to present the energy situation in Mozambique and assess the potential for energy generation from widely available renewable sources including residues from agricultural crops and forest industry. The country is endowed with great potential for biofuels, solar, hydro and wind energy production. The energy production today is, however, far from fulfilling energy needs of the country, and the majority of people are still not benefiting from these resources. The potential of total residues from agricultural sector and forest industry is estimated to be around 128 PJ. This amount of energy covers almost half of the combined production of charcoal and firewood which amounted to approximately 298 PJ in 2006. However, such amount of energy resources is wasted and is not visible on national energy statistics.     

Modern bioenergy from agricultural and forestry residues in Cameroon: Potential,challenges and the way forward

Environmentally benign modern bioenergy is widely acknowledged as a potential substitute for fossil fuels to offset the human dependence on fossil fuels for energy. We have profiled Cameroon, a country where modern bioenergy remains largely untapped due to a lack of availability of biomass data and gaps in existing policies. This study assessed the biomass resource potential in Cameroon from sustainably extracted agricultural and forest residues. We estimated that environmentally benign residues amount to 1.11 million bone dry tons per year. This has the potential to yield 0.12–0.32 billion liters of ethanol annually to displace 18–48% of the national consumption of gasoline. Alternatively, the residues could provide 0.08–0.22 billion liters of biomass to Fischer Tropsch diesel annually to offset 17–45% of diesel fuel use. For the generation of bioelectricity, the residues could supply 0.76–2.02 TW h, which is the equivalent of 15–38% of Cameroon's current electricity consumption. This could help spread electricity throughout the country, especially in farming communities where the residues are plentiful. The residues could, however, offset only 3% of the national consumption of traditional biomass (woodfuel and charcoal). Policy recommendations that promote the wider uptake of modern bioenergy applications from residues are provided.     

Photobiostimulation of anaerobic digestion by laser irradiation and photocatalytic effects of trace metals and nanomaterials on biogas production

Biogas generation from the latent energy in biomass is one of the most attractive renewable energy sources. This can be attributed to the environmental friendly nature of the process and its less energy requirements. This article reviews the anaerobic digestion of biomass (livestock manure and crop residues) for biogas and methane production as a source of renewable energy. Furthermore, this study investigates the enhancement of biogas and methane production using light and laser radiations. The laser radiation accelerates bacterial division and growth, where this process is termed as “photobiostimulation.” Additionally, laser radiation photoactivates the inactive enzymes. The results of this literature review showed that the irradiation of methanogenic bacteria with laser sources increased the biogas production by one and a half fold the traditional method of biogas production. The simultaneous irradiation of both nanomaterials and methanogenic bacteria using laser radiation increased the biogas volume by twofolds the biogas volume resulted from the traditional method of biogas production.